Telegraph signaling system



W. e. STANLEY 1,953,273 TELEGRAPH SIGNALING SYSTEM April 3, 1934.

.Filed Oct. 8, 1932 STAT|0 STATION 8 STATION A INVENTOR WILLIAM G. STANLEY ATTORNEY Patented Apr. 3, 1934 TELEGRAPH SIGNALING SYSTEM William G. Stanley, New York, N. Y assignor to Postal Telegraph-Cable Company, New York, N. Y., a corporation of New York Application October 8,

9 Claims.

The present invention relates to telegraph signaling by means of signals composed of positive and negative impulses. The arrangement, while not confined to such use, is especially applicable to a telegraph way-wire system, that is, to a system in which a number of stations are in circuit on a single wire, and in which provision is made for communication in but one direction at any one time. When such systems are used it is necessary that any station along the line be able to break in and cause cessation of communication between other stations, in order that rush business be given a preference. In addition, it is frequently necessary that a receiving station be arranged so that the operator thereat may interrupt reception and transmit to the transmitting operator a request for repetition of a portion of the message, or for other information.

One of the objects of the system is to provide an arrangement for breaking in on a circuit over which signals are being sent, such breaking in being effective to give the transmitting operator a signal and to prevent further transmission until the operator has complied with the break request.

Another object of the invention is the arrangement of the break relay circuit, so that a maladjustment of the break relay at any station will not interfere with, or react upon, the reception of telegraph signals at that station.

Still another object of the arrangement herein disclosed is to provide a means for compensating for the biasing effects of earth currents, or other foreign potentials affecting the receiving relay; and to accomplish such compensation with the use of a single pole of battery. I I

The mode of accomplishing the various objects set forth above may be clearly understood by referring to the following description taken in connection with the attached drawing. The novel elements of the arrangement are pointed out in detail in the annexed claims.

The single drawing shows at A and Ctwo terminal stations, and at B an intermediate station. There may be a plurality of such intermediate stations. The equipment and circuit arrangement is similar at all stations, except that a two-pole grounded current supply is shown at station C in place or" the ungrounded current supply shown at stations A and B.

The system will now be described in detail with reference to the drawing. When the circuit is idle, the relays and switches are in the positions shown, and the line circuit may be traced from ground at station A, through resistance 7, contact 1932, Serial No. 636,869

A and armature D of switch 1, line or right-hand winding of polar relay 2, line winding (upper) of relay 3, line section L, resistance 37, contact A and armature D of switch 31, line winding of relay 32, line winding of relay 33, line section L1, line winding of relay 62, line winding of relay 63, armature D and contact A of switch 61, resistance 6? to ground. Since both ends of the line are thus grounded, there is no current flow under such conditions and all relays remain in their normal positions. It is to be noted that the battery at intermediate station E is not grounded and, consequently, although one terminal of this battery 36) is always connected to the two lines under the conditions described above, there is no flow from the battery.

When signals are to be transmitted, the operator at the transmitting station depresses the foot switch, as 1, and then transmits. Assuming that there is business to be transmitted from station A, the operator depresses switch 1 and then operates the keyboard 8 of the printer mechanism. The keyboard is illustrative only and might be replaced by a Morse key, bug, tape transmitter, or other transmitting device. The making and breaking of the contacts of keyboard 8 causes the series connected relays 4 and 5 to operate in accordance with the letters transmitted and positive and negative signals are thus sent over the line. The circuit at this time comprises ground, tongue of relay 4, contact A or B of relay i, resistance and battery 6, or vice versa, contact A or B of relay 5, armature of relay 5, contact B and armature D of switch 1, line winding of relay 2, line winding of relay 3, line section L, resistance 37, contact A and tongue Dof switch 31, line winding of relay 32, line winding of relay 33, line section L1, line winding of relay 62, line winding of relay 63, armature D and contact A of switch 61, resistance 67 to ground. Relays 2, 32 and t2 follow the signals, the current in their line windings being sufficient to overcome that in the biasing windings, and as these relays operate the printer magnets 9, 39 and 69 are operated and the transmit-ed message is printed. Relays 3, 33 and 63 are not operated by these signal impulses since the current through their lower or biasing windings is adjusted to a high enough value to hold their armatures on the spacing or 3 contacts. The biasing current for relay 3 is supplied over a circuit from battery, through adjustable resistance 10, and the lower winding of relay 3 to ground. The corresponding relays at the other stations have similar biasing circuits. The operators adjust resistances 10, 40 and '70 so that the biasing current is greater than the normal line current.

Let us assume now that the operator at station A continues to transmit to station C, and that the operator at the latter station wishes to confirm a portion of the message, or for some other reason wishes to break. The operator at station C then depresses foot switch 61 and thus alters the connection at that station. The current from line section L, may now be traced through the line windings of relays 62 and 63, tongue D and contact B of switch 61, contact A of relay 64 to the negative pole of battery and thence to ground. When the next marking signal is transmitted from station A, the current is increased from its normal value and causes operation of relays 3, 33 and 63.

Operation of the three relays mentioned last completes a circuit at each station to prevent transmission. Only one of these circuits will be traced, since the others are duplicates. At station A operation of relay 3 completes a circuit from battery through contact A thereof and through the right-hand operating winding of relay 11 to ground. If switch 1 remains in its operation position this relay looks over a circuit through its left-hand contacts. Operation of relay 1i completes a circuit from battery through the windings of relays 4 and 5 and the righthand contacts of relay 11 to ground. This circuit shunts out the transmitting contacts of keyboard 8 and no further transmission can take place until relay 11 is de-energized. Provision is made for such de-energization when switch 1 is released, at which time a direct circuit to ground is supplied to the locking battery, through armature E and contact B of switch 1. This restores station A to condition for receiving and the breaking station may then transmit.

Station 13 may break either station A or C in a similar manner. It is to be noted, however, that the battery at station B is not grounded. This necessitates placing the battery in series with the line which is accomplished by the contact arrangement of switch 31. This station is shown with ungrounded battery, because it frequentlyoccurs in practice that a small way station will be furnished with a single current source, and because this is a convenient method of reversing line current of an operating value for relays 3, 33 and 63 when the switch at station 33 is depressed.

Another feature of this circuit is the arrangement of resistances in the bias circuits of relays 2, 32 and 62. In each instance these relays are arranged in the form of a Wheatstone bridge having two arms adjustable sothat the value of the biasing current may be readily varied to conform to line conditions. The bridge arrangement makes it possible tocompensate for either positive or negative ground currents with the use of a single battery at the station, and permits adjustment over a range of positive and negative values of current to be made by gradual steps. Adjustment of the current for compensating is made in the case of relay 2 by altering the position of contact 18 on resistance 17. Since resistance 17 forms the balancing arms of a Wheatstone bridge, across the conjugate arms of which the biasing winding of the relay is connected, the resultant upset in the balance causes current to flow through the winding in the direction and amountdesirable. The corresponding circuits for other relays are exactly similar.

Th r uit e c b d a v ev ts y maladjustment of the break relays as 3, 33 and 63 from interfering with, or reacting on, the receiving circuits. This is obviously so, since there is no connection between these relays and the receiving apparatus, the relays merely acting to short-circuit the transmitters and prevent their operation until the receiving circuits are restored to normal. Prior arrangements for breaking often provided for breaking the circuit to the receiving mechanism, and thus when the break relay was out of adjustment reception was interfered with, or, in some instances, prevented.

For convenience, the switches, as 1, 31 and 61, are arranged to be operated by foot pressure, since the operator needs both hands to operate a printing telegraph keyboard. When, however, trans mission is to take place by means of an automatic transmitter in accordance with perforated, or other prepared tape, switches, as 1, 31 and 61, may be replaced by a relay having the same contact arrangement as these switches. Such relays are then operated by the switch, integral with automatic transmitters of, for example, the Teletype type, for starting and stopping the transmitter. The switch may be controlled in the same manner commonly used when automatic transmitters are employed, namely, in accordance with the amount of slack in the tape between a perforator and the transmitter.

The above has been given by way of description only, and is in no way to limit the scope of the appended claims.

What is claimed is:

In a telegraph system comprising at least three stations along a line, means including a receiving relay at each station permanently connected in series with the line to signal between said stations with polar signals, means at each station to increase the signal strength, and means at each station responsive to such increase in signal strength to prevent transmission.

2. In a telegraph signaling system comprising at least three stations connected by a line, the

combination of transmitting and receiving means at each station including a polar receiving relay permanently connected in series with said line, means actuated by said transmitting means at any station to send polar signals to all other stations for operating said polar receiving relays, switching means at each station operable to increase the signal strength, relay means at each station connected in said line and operable by signals of increased strength, and means operated by said relay means to prevent actuation of said signal sending means by said transmitting means at all stations.

3. In a telegraph signaling system comprising a sendingand a receiving station, and a line connecting said stations normally grounded at both said stations, a receiving relay at each station p ma nt onn c ed n, sa d i e, me n a said transmitting station for connecting transmitting apparatus and a current source to said line and to remove the ground therefrom to permit transmission over said line, means similar to said first mentioned means to connect an aiding current source to said line at said receivingstation, and means responsive to increased line current provided by said two cur-rent sources to prevent operation of said transmitting apparatus.

t l h, s nal n sy em c r n a a l o nded. ne, a plu lit o l raph tiOHS 310113 aid l ne and clu in ii Q r inal stations and at least one intermediate station, ansm t in nd eceivin equ pment at each said station, said receiving equipment being connected for operation from said line and including a receiving relay at each station permanently connected in series with said line, and said transmitting equipment being disconnected from said line, switching means at each said station to connect the transmitting equipment, a current source controlled by the transmitting equipment in series with said line, and means in said line at each station to prevent effective operation of all said transmitting apparatus while more than one of said switching means is operated.

5. In a telegraph circuit including a line relay subject to interfering ground potentials, means for compensating for the effect of ground potentials on said relay comprising a biasing winding on said relay, a single current source supplying said biasing winding, and means to adjust the current flow through said winding from said source in both amount and direction, said means including a Wheatstone bridge across the conjugate arms of which is said current source and in the galvanometer circuit of which is said biasing winding, said bridge having readily adjustable balancing arms,

6. In a telegraph system comprising at least three stations connected by a line, the combination of transmitting means at each station, polar receiving and break relay means at each station permanently connected in said line, means actuated by said transmitting means at one station to send polar signals to all other stations for operating the polar receiving relay means thereat, switching means at each station operable to increase the signal strength for causing the operation of said polar break relay means at all stations, and means responsive to the operation of said polar break relay means for preventing transmission of signals by said transmitting means at all stations.

7. In a telegraph signaling system comprising three or more stations connected by a line, the combination of a polar receiving relay at each staticn connected in series with said line, a break relay at each station connected in series with said line, a source of signaling current at each station, means at each station for transmitting signals therefrom over said line, switching means at each station controlling the connection of the current source thereat to said line, means whereby simultaneous operation of the switching means at two stations causes the flow of current over the line to increase thereby to cause the operation of the break relays in all stations, and means responsive to the operation of each break relay to prevent the transmission of signals from the corresponding station.

8. In a telegraph signaling system comprising three or more stations connected by a line, the combination of a polar receiving relay at each station connected in series with said line, a break relay at each station connected in series with said line, a source of signaling current at each station, means at each station for transmitting signals therefrom over said line, switching means at each station controlling the connection of the current source thereat to said line, means whereby simultaneous operation of the switching means at two stations causes the flow of current over the line to increase thereby to cause the operation of the break relays at all stations, means responsive to the operation of each break relay to prevent the transmission of signals from the corresponding station, and a resistance at each station normally connected in series with said line and removed from said line by operation of the switching means thereat.

9. In a telegraph signaling system comprising three or more stations connected by a line, the combination of a polar receiving relay at each station connected in series with said line, a break relay at each station connected in series with said line, a source of signaling current at each station, means at each station for transmitting signals therefrom over said line, switching means at each station controlling the connection of the current source thereat to said line, means whereby simultaneous operation of the switching means at two stations causes the flow of current over the line to increase thereby to cause the operation of the break relays at all stations, means responsive to the operation of each break relay to prevent the transmission of signals from the corresponding station, and means whereby when the marking signal is transmitted from any station the current over the line flows in one direction and when a spacing signal is sent from any station current flows over the line in the opposite direction.

WILLIAM G. STANLEY. 

